Dark circles in skin beneath the eye can contribute to an overall appearance of fatigue and/or aging and it is highly desirable to reduce the appearance of such circles in order to effect a more youthful and energetic look. Thus, a multitude of cosmetic or skin care products exist in the marketplace with claims to reduce the appearance of these dark circles.
Such dark circles are attributed to a number of causes, but are mainly the result of heme catabolite, inflammation, and melanin accumulation. Heme is the prosthetic group of heme proteins, such as hemoglobin, a major component of blood. Heme is leaked by dilated blood vessels and becomes free heme, which catalyze the production of free radicals and is pro-inflammatory and pro-oxidative. Heme oxygenase is a rate limiting enzyme that catalyzes the degradation of heme to biliverdin which is subsequently converted to bilirubin, carbon monoxide and iron which will be stored in ferritin, all of which have well described antioxidant and anti-inflammatory properties. Heme oxygenase 1 (HO-1) is an inducible isoform. Stimulating HO-1 would, in turn, stimulate the scavenging of heme thereby reducing the appearance of dark circles. It is therefore desirable to have a cosmetic active ingredient which is capable of stimulating the production of HO-1 in the skin under the eyes.
Further, many cosmetic compositions which address dark circles address additional skin imperfections occurring in the eye area in order to further reduce the “tired eyes” appearance. For example, products addressing dark circles often further address puffiness (i.e, “eye bags”), wrinkles, and dryness in the eye area. To do so, the product generally contains multiple cosmetic active ingredients, each directed to one of the specific type of imperfections. The use of multiple active ingredients increases the difficulty in formulating such products as well as increases the raw material costs. Thus, it is desirable to have a single cosmetic active ingredient which is capable of addressing multiple cosmetic concerns associated with the eye area.